Remote site protective alarm system

ABSTRACT

THE PROTECTIVE SYSTEM DISCLOSED HEREIN COMPRISES AN ANTENNA WHICH IS PLACED ADJACENT THE AREA TO BE PROTECTED, A MASTER CONTROL AND POWER UNIT WHICH MAY BE POSITIONED AT A REMOTE AREA, AND A PLURALITY OF REMOTE SIGNAL STATIONS POSITIONED AT DESIRABLE AREAS WHERE A SIGNAL IS TO BE PRODUCED IF A FOREIGN BODY IS PRESENT IN THE AREA BEING PROTECTED. THE MASTER POWER AND CONTROL UNIT COMPRISES A SOURCE OF RADIO FREQUENCY ALTERNATING CURRENT AND, MORE SPECIFICALLY, A MODIFIED HARTLEY OSCILLATOR, A FIRST SECONDARY COIL POSITIONED ADJACENT THE PRIMARY COIL OF THE OSCILLATOR TO WHICH THE ANTENNA IS CONNECTED, A SECOND SECONDARY COIL ADJACENT THE PRIMARY COIL OF THE OSCILLATOR WHICH IS CONNECTED TO AN AMPLIFIER WHICH, IN TURN, CONTROLS A FIRST RELAY THAT IS NORMALLY ENERGIZED. THE NORMALLY ENERGIZED RELAY, IN TURN, CONTROLS A SECOND RELAY THAT IS NORMALLY ENERGIZED AT EACH OF THE REMOTE STATIONS. WHEN A FOREIGN BODY IS PRESENT AT THE AREA BEING PROTECTED, A CHANGE IN LOAD OF THE OSCILLATOR CIRCUIT IS PRODUCED CAUSING A CHANGE IN THE SIGNAL SUPPLIED BY THE SECOND SECONDARY COIL TO THE AMPLIFIER, IN TURN, DE-ENERGIZING SUCESSIVELY THE RELAYS TO PRODUCE A WARNING SIGNAL AT EACH REMOTE STATION.

J;n.26,1197.1 'C.S.KONTO'S, 3,559,202

REMOTE SITE PROTECTIVE ALARMSYSTEM Filed July 51: 1967 4 Sheets-Sheet 1 2 I 1/ n I8 ,19- 'f v MODIFIED AMP |F\ER RELAY OSCILLATOR ,sqmsemr comraoa. l v A f v I I T 6 a E POWER POWER a SUPPLY TRANSFORMER I I. I INVENTOR. V S 5 CONSTANTINE S. Kom'os [34AM WCAD ATTORNEYS Jan; 26,1911- '7 gamma; 3, 59 2 v REMOTE SITE PROTECTIVE ALARM SYSTEM Filed July 51, 1967 4 Sheets-Sheet a I I VENTOR. CONSTANTINE. S. KEN-r05 T ATTORNEYS Jan. 26,1971 c. s. KONTOS 3, 2

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NVENTOR. CON-STANTINE S. ONTOS BY wwwfl ATTORNEYS 1 Ja 9 I c. s. KONTOS REMOTE SITE PROTECTIVE ALARM SYSTEM 4 Sheets-Sheet Filed July 51, 1967 1 VENTOR. CONSTANTINE. S. l c 'ros m, Km

ATTORNEYS United States Patent 3,559 202 REMOTE SITE PROTECTIVE ALARM SYSTEM Constantine S. Kontos, Detroit, Mich., assignor to Neo- Guard, Inc., Allen Park, Mich., a corporation of Michigan Filed July 31, 1967, Ser. No. 657,187 Int. Cl. G08b 13/26 US. Cl. 340-258 19 Claims ABSTRACT OF THE DISCLOSURE source of radio frequency alternating current and, more specifically, a modified Hartley oscillator, a first secondary coil positioned adjacent the primary coil of the oscillator to which the antenna is connected, a second secondary coil adjacent the primary coil of the oscillator which is connected to an amplifier which, in turn, controls a first relay that is normally energized. The normally energized relay, in turn, controls a second relay that is normally energized at each of the remote stations. When a foreign body is present at the area being protected, a change in load of the oscillator circuit is produced causing a change in the signal supplied by the second secondary coil to the amplifier, in turn, de-energizing sucessively the relays to produce a warning signal at each remote station.

This invention relates to a protective system and particularly to a system for sensing the presence of foreign objects such as human bodies in a specific area.

BACKGROUND OF THE INVENTION It has heretofore been suggested that one type of protective system which can be used to indicate the presence of a foreign body in a specified area comprises an antenna to which radio frequency energy from an oscillator is supplied. The presence of a foreign body adjacent the antenna produces a change which can be sensed in order to actuate a warning device. Such devices have been found to be quite sensitive, difficult to maintain, easily tampered with and the sensing circuits have been found to be quite complex.

Among the objects of the present invention are to provide a protective system which is relatively simple, practical, capable of detecting objects which are both conductive and nonconductive, which can be easily maintained, which cannot be tampered with without producing a warning signal; which is reliable and will operate even in the event of power failure.

SUMMARY The protective system disclosed herein comprises an antenna which is placed adjacent the area to be protected, a master control and power unit positioned at a remote area, and a plurality of remote signal stations positioned at desirable areas where a signal is to be produced if a foreign body is present in the area being protected. The master power and control unit comprises a source of radio frequency alternating current and, more specifically, a

"ice

modified Hartley oscillator, a secondary coil positioned adjacent the primary coil of the oscillator to which the antenna is connected. The secondary coil adjacent the primary coil of the oscillator is also connected to an amplifier which, in turn, controls a first relay that is normally energized. The normally energized relay, in turn, controls a second relay that is normally energized at each of the remote stations. When a foreign body is present at the area being protected, a change in load of the oscillator circuit is produced causing a change in the signal supplied by the second secondary coil to the amplifier, in turn, deenergizing successively the relays to produce a warning signal at each remote station.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of the protective system embodying the invention.

FIG. 2 is a partly diagrammatic view of one of the portions of the system.

FIG. 3 is a schematic wiring diagram of a portion of the system.

FIG. 4 is a schematic wiring diagram of another portion of the system.

FIG. 5 is a schematic wiring diagram of another portion of the system.

FIG. 6 is a schematic wiring diagram of another portion of the system.

FIG. 7 is a schematic wiring diagram of another portion of the system.

GENERAL DESCRIPTION Referring to FIG. 1, the protective system is shown diagrammatically as intended to protect and produce a warning when a foreign body such as a human body approaches an object O at a remote point. An antenna 10 in the form of a single wire is positioned adjacent or in contact with the object O and extends to a master power and control unit 11 at a remote station. The master power and control unit is, in turn, connected to remote signal stations 12, 13 that are positioned at desired locations where a warning Will be produced when a foreign body is present adjacent the object 0.

As further shown in FIG. 1, the power remote control station 11 is adapted to be connected by a line 14 to an external power source that energizes a power transformer 15 and produces direct current through a power supply unit 16 that supplies a modified oscillator 17 to which the antenna 10 is connected. A signal from the oscillator 17 is supplied to an amplifier and signal sensor 18 which controls a relay 19, as presently described.

For purposes of safety and ease of maintenance, each of the units 11, 12, 13 is sealed and connected to the other units by plugs and cables, as presently described, so that the units can be readily removed and replaced if required. As further explained hereinafter, in the event of disconnection of any one of the units 11, 12, 13 from the other, a signal is produced at the stations 12, 13. Each of the remote stations 12, 13 is provided with an auxiliary power source and is constructed in a manner such that in the event that the primary power source is disconnected from the station, a warning signal is produced by power supplied from the secondary power source.

POWER AND CONTROL UNIT The various components of the power and control unit are placed in a single housing 20 as shown in FIG. 2.

The modified oscillator 17 is adapted to be plugged into a socket 21 to which the remainder of the units 15, 16, 18, 19 of the power unit are connected. These units are combined in a single circuit board 22 except for the signal lights 23, 24.

The circuit board 22 is connected to another socket 25 which forms the connection to the remote stations 12, 13 and to the antenna. As previously discussed, the housing 20 is sealed so that it can be readily determined if the housing has been tampered with. A plug 26 is provided for external power to the power and control unit.

Referring to FIG. 3, which is a wiring diagram of the portion of the system on circuit board 22, the power transformer 15 receives power from an external power line through plug 26 and reduces the voltage of the incoming power and supplies it across the diodes 30, 31 and capacitor 32 to produce a DC power supply in lines 33, 34 that extends to connectors 5, 7 of socket 21. These, in turn, supply power through a plug 21a of a modified oscillator module 17 (FIG. 4) which comprises a NPN transistor 35 to the base of which parallel connected capacitors 36, 37, the latter of which is adjustable, are connected. A bias resistor 38' is connected to the collector of tranisstor 35. The oscillator further includes a primary coil 38 in series with the capacitors 36, 37 and a capacitor 39 connected in the line extending from the primary coil 38 to the emitter and forming a tank circuit. A tap 38a extends from the primary coil 38 to the line connecting the capacitor 39 to the emitter. A filter bypass capacitor 39a is connected between the collector of the transistor 35 and the line connecting the coil 38 and the capacitor 39. The modified oscillator further includes a first secondary coil portion 40, one end of which is connected to a point 3 on plug 21a. The

other end of the coil 40, point b, is connected to point 6 in plug 21a. A second coil portion 41 is connected in series with the coil portion 40 at b. A line 43 extends from point a to the capacitor 39 and common power line 7. The plug 21a on module 17 is adapted to be inserted into the socket 21 (FIG. 2) so that the module 17 is sealed within the housing 20. In addition, a jumper wire is provided between points 2 and 8 of plug 21a. Referring to FIG. 3, when the plug 21a is inserted into the plug 21, power is supplied to the oscillator through connectors and 7. When power is supplied to the oscillator, it oscillates at a radio frequency preferably on the order of 50-80 kc.

The frequency induced in the portion 41 of the secondary coil that extends to point 6 is applied through a resistor 54a to the base of a transistor 50 that forms a part of the amplifier and signal sensor 18 (FIG. 3). The collector of transistor 50 is, in turn, connected through a capacitor 51 and diode 51a to a silicon controlled rectifier 52. Capacitor 53 comprises a power supply filter. Capacitor 54 comprises a DC blocking condenser. Resistor 55 comprises a bias resistor for transistor 50 and resistor 56 comprises a load resistor. Capacitors 53, 54 and resistors 55, 56 are selected to give proper gain and are connected in such a manner that under normal operation of the oscillator and in the absence of a foreign body at the area being protected, current flows continuously through the coil 57 of a relay R holding contacts 58, 59 into circuit completing relation so that the same voltage is applied to points 6 and 7 of socket 25. At the same time, the light 24 is energized.

As shown in FIG. 3, point 2 of socket 21 is connected to a wiper 85 of a variable resistor 86 connected across points 1 and 3. This places a portion of the resistor in series with the point 0 in FIG. 4 and is utilized to adjust the sensitivity of the system. As shown in FIG. 3, point 8 of socket 21 is connected by a line 87 to point 8 of socket 25. The antenna 10, in turn, is connected to point 8 of socket 25 by a wire extending through the plug 25a which is used to connect the remote stations to the master power and control unit. Since a jumper is provided across points 2 and 8 of socket 21a, the antenna is thus connected to point 0 through a portion of the resistor 86. As a net result, the antenna 10 is inductively coupled to the primary coil of the oscillator. In the structural unit shown in FIG. 2, the variable resistor 85, 86 is designated by a reference numeral V and externally accessible screw S is provided for making the adjustment.

REMOTE STATIONS As further shown in FIG. 5, the first remote station 12 comprises lines 60, 61, 62 that extend to a socket 25b. As shown in FIG. 7, a cable C having one or more plugs 25:: and a common plug 25d is provided for connecting the remote units to the master power and control unit. Specifically, a plug 25c is inserted in a corresponding socket in the remote unit or station and plug 25d is inserted in socket 25 of the master power and control unit. Line '60 extends to one contact 63 of a relay R Line 61 extends to the coil 64 of the relay R and thereafter through a two-position switch 65 to line 62. Line 62 extends through the switch 65 when it is in on position to a contact 66 of the relay R Contacts 67, 68 are associated with contacts 66, 63.

On light 69a and ed light 69b are connected to the on and oil contacts, respectively, of a second portion of switch 65. A battery 70 and associatedprotective diodes 71 and resistors 72 are provided in parallel with the coil 64 when switch 65 is in the off position so that the battery is charging. The battery is also being energized when the switch 65 is in the on position. A siren 73 is connected between contact 67 and a point between the battery 70 and resistor 72.

When the switch 65 is in on position and the oscillator is energized causing the relay 57 to be energized, current flows through lines 60, 62 energizing the relay R at the remote station 12 to bring contacts 66, 67 out of contact and contacts '63, 68 into contact. In the presence of a foreign body adjacent the antenna, a change occurs on the load on the secondary coil 41 which, in turn, affects the signal applied to the transistor 50 and thereby causes the relay R to become de-energized so that the contacts 58, 59 are broken. This will interrupt the flow of current to lines 60, 62, de-energizing the relay 64, bringing the contacts 66, 67 into contact to actuate the siren.

A similar energization of the siren will occur in the event that the connection between the remote unit 12 and the master control unit 11 is broken or the power to the master control unit is cut oil. In such event, the relay 64 will become de-energized and the auxiliary power from the battery 70 will again cause the siren to be energized.

The remote station 13 shown in FIG. 6 is substantially identical to the remote station 12 except that an additional power connection 75 is provided where additional power is needed to control a signal device that requires a large amount of power, for example, a large siren, flasher or the like. In this device, a second relay R is provided and is controlled by an additional pair of contacts 77, 78 by the coil 64'. The additional power heretofore is supplied across the lines 79, 80 so that when the coil 64' is de-energized, the coil 76 of relay R is energized to complete the circuit to the receptacle 81 to which the auxiliary signal device is connected. In the event that the plug 75 is disconnected, the relay 76 will become de-energized completing contacts 82, 83 that will energize the siren 73 of the control unit 13.

Although the invention has been described in connection with the use of relays, solid state switching devices can also be utilized. Accordingly, the term relay as used herein is intended to cover any switching device which will achieve the intended purpose.

Similarly, the connection of the secondary coil portions may be modified. For example, the connections of points a and b may be reversed so that point b in FIG. 4 can be connected to the common line extending to point 5 while point a extends to point 6. Similarly, the connections may be changed by connecting point a to the line leading to point 5, connecting point b to point 3, providing a jumper between points 1 and 5 and 2 and 6, after-removing the jumper between points 2 and 8, and connecting point c to point 8.

OPERATION In use, the antenna is placed with the free end thereof adjacent or in connection with the object O which is to be protected. A wire extends from the antenna to the master power and control unit 11 at a remote point. The remote signal stations 12, 13 are positioned at desired signal points and are connected to the master power and control unit 11 at a remote point. When plug 26- is connected to an external alternating current power source,

power is supplied to the modified oscillator producing radio frequency alternating current. In order to provide proper operation, each of the remote stations has the switch thereon manually actuated to the on position. By means of the resistor 86, the sensitivity of the system is adjusted so that a signal is provided to the amplifier and signal sensor 18 energizing the relay R in the master power and control unit so that the relays R R and R in the remote stations are energized.

When a foreign body such as a human body approaches or comes into contact with the object O, the load on the secondary coil of the transformer changes so that the signal applied to the transistor 35 is, in turn, changed so that the relay R is de-energized and, in turn, relays R R and R are de-energized. This produces a warning signal at each of the remote stations.

In the event that the cable C is disconnected, the external power plugs 26 or 75 are disconnected, the relays will also be de-energized and the warning signal will be energized by power from the auxiliary power sources 70, 70.

I claim:

1. In a system for sensing an object, the combination comprising:

(a) a source of alternating current;

(b) an antenna connected to the source for receiving alternating current to provide an electrical load that varies as the position of an object adjacent the antenna;

(c) an electrically actuated relay;

(d) a signal sensor connected to the source for receiving electrical power, and to the relay for actuating it; and

(e) a transformer having a primary coil receiving alternating current, and a secondary coil inductively coupled to the primary coil for receiving electrical power, the secondary coil being so connected to the antenna as to form an electrical load having a magnitude that varies substantially in accordance with the load of the antenna, and being connected to the signal sensor such that power being received by the signal sensor varies inversely as the load of the antenna, whereby the relay is actuated in response to the motion of an object adjacent the antenna.

2. The combination as defined in claim 1, in which the source of alternating current comprises a source of electrical power, and an oscillator connected to said source to provide radio frequency oscillations for the antenna.

3. The combination as defined in claim 1, including a slurce of eelctrical power connected to the relay for energizing it at such times as an object is spaced from the antenna, and wherein the signal sensor is operative to de-energize the relay in response to the object being moved to a position adjacent the antenna.

4. The combination as defined in claim 1, including a variable resistor connected in series with the antenna to adjust the manner in which the relay is actuated in response to an object approaching the antenna.

5. The combination as defined in claim 1, in which the source of alternating current comprises a source of electrical power, and an oscillator circuit connected to receive power from said source to provide radio frequency oscillations in the primary coil of the transformer.

6. The combination set forth in claim 1 wherein said source of alternating current comprises an oscillator including a tank circuit,

said primary coil comprising a part of the tank circuit of said oscillator.

7. The combination set forth in claim 6 wherein said oscillator includes a NPN transistor,

a pair of capacitances connected in parallel between the base of said transistor and the primary coil,

a tap extending from said primary coil to the emitter of said transistor.

8. The combination set forth in claim 1 wherein said secondary coil comprises a first coil portion connected to said antenna and a second coil portion connected to said signal sensor.

9. The combination set forth in claim 1 including a second relay connected to said first mentioned relay and normally energized when said first mentioned relay is energized, and

a signal device connected to said second relay and operable upon de-energization of said second relay to produce a signal.

10. The combination set forth in claim 9 including a battery associated with said signal device and operable upon de-energization of said second relay to energize said signal device.

11. The combination set forth in claim 9 including an auxiliary source of energy associated with said second relay for normally providing energy to said signal device when said second relay is de-energized.

12. The combination set forth in claim 9 wherein said second relay and said signal device are positioned at a remote station.

13. A system as defined in claim 1, including a line connecting the primary coil to the secondary coil.

14. The combination set forth in claim 1 including a variable resistor in series with said antenna.

15. A system for sensing the motion of an object, compnsing:

(a) a source of electrical power;

(b) an oscillator circuit including a primary coil connected to the source of electrical power to provide oscillating power;

(c) a secondary coil inductively coupled to the primary coil to receive oscillating power;

((1) an antenna connected to the secondary coil to be energized by oscillations received from the secondary coil, and to provide an electrical load on the secondary coil that increases in accordance with the approach of an object adjacent the antenna;

(e) an electrically actuated relay, and

(f) an amplifier connected to the secondary coil to receive power that is reduced in accordance with the manner in which the load of the antenna is being increased, and connected to the relay to actuate it in response to said load.

16. A system as defined in claim 15, in which said oscillator circuit includes an NPN transistor, a pair of capacitances connected in parallel between the base of said transistor and the primary coil, and a tap connecting the primary coil to the emitter of the transistor.

17. The combination set forth in claim 15 including a remote signal station,

a second relay connected to said first mentioned relay and normally energized when said first mentioned relay is energized, and

an external signal device connected to said second re- 7 lay and operable upon de-energization of said second 3,041,592 6/1962 Schmidt 340258C relay to Produce a slgnal- 3,129,414 4/1964 Rice 340-258C 18. The combination set forth in claim 17 including a battery operable upon de-energization of said second re- 3234535 2/1966 Schordme 340 213 lay to energize said signal device. 3,392,349 7/ 1968 Bartley 33l117X 19. The combination set forth in claim 17 including an 0 auxiliary external source of energy C associated with said ALVIN WARING, Prlmary Examlner second relay for normally providing energy to said signal PALAN Assistant Examiner device when said second relay 1s de-energized.

10 US. Cl. X.R.

References Cited 33 11 17 UNITED STATES PATENTS 2,701,874 2/1955 Mears 340-276 

